Role of adherent cells in immune responses to phytohemagglutinin and concanavalin A.

The roles of adherent and nonadherent T cells in the responses to phytohemagglutinin (PHA) and concanavalin A (Con A) were studied. [3H]thymidine uptake by mononuclear cells from human thymus and peripheral blood was used to measure the relative influence of monocytes and B cells on the responses to these mitogens. The response to Con A was dependent on two populations of T cells, one adherent to cotton or nylon and the other nonadherent. The first population appeared to potentiate the latter. In contrast, the response to PHA was dependent only on the nonadherent T cell subpopulation. The responses to PHA and to Con A were both dependent on monocytes to approximately the same extent, but the response to Con A, unlike the response to PHA, was also slightly dependent on B cells.